Where can I find tires 265 - 70 - R20
whatv other tire is compatible with 225 65r 16
315/70/17
275/65-16 or 235/75-16 Either of these sizes is an excellent substitute.
Your tire dealer can help you with that.
205/60-16 or 245/50-16. Either of these sizes is compatable with your 225/55-16.
175/80R13
215/70R20 is 32 inches tall But without a specific wheel width or desired tire width a "Correct" exact tire size is not possible. To figure out what you need search "Tire Size Calculator on Google and choose the Miata.net choice
Look at the sticker on your fuel cap, on the bottom left it will have all compatible tire and rim sizes.
Look on the driver's door support and there is a decal with sizes and tire pressures. DO NOT mix tire sizes as it will disrupt the antilock brakes.
Yes, it's compatible
The best way to tell if the two tires will interchange is to check the sizes on each tire. Both vehicles mentioned in the question came equipped with multiple sizes from the factory so it's not possible to determine whether they are compatible. Tire size is listed on the sidewall of the tire and will look like: P215/65R16 Without going into too much detail, if both tires are the same size they are compatible. Otherwise, if they are not the same size, write both sizes down and call a local tire store and ask if they may fit. See wikipedia's article on tire sizing: http://en.wikipedia.org/wiki/Tire_size
No, never mix tire sizes.